This invention relates to a method for operating a battery of coke ovens, and more particularly to a coke oven operating method which accomplishes an increase in production and a decrease in quantity of heat required for carbonization.
Conventionally, the operation of a coke oven is carried out according to a schedule for charging and discharging operations with respect to a battery of coke ovens (hereinafter referred to as "oven charge-discharge schedule") which is prepared so as to properly distribute the number of operations per one day among working teams, to thereby permit operators to take a rest during working and the amount of working to be equalized among the working teams. Also, the oven charge-discharge schedule is so prepared that the number of operations is distributed depending on working hours for each of former and latter halves of the working with a rest period being interposed therebetween.
FIG. 3 illustrates an example of such an oven charge-discharge schedule, wherein the number of carbonization chambers is set to be 100 and the number of operations per one day is set to be 132. In FIG. 3, a laterally extending line on an upper stage indicates a series of continuous unit oven workings of the previous day and a laterally extending line on a lower stage is a series of continuous unit oven workings of the day. A space between the upper line and the lower line indicates a period of time required for shifting between working teams and a rest period for each of the working teams. Feedstock coal charged in a coke oven at times when oblique lines extending between the upper stage and the lower stage intersect the laterally extending line on the upper stage is discharged at times when the oblique lines intersect the line on the lower stage. The operating process of FIG. 3 will be referred to as "first process" hereinafter.
Another operating process is disclosed in Japanese Patent Application Laid-Open Publication No. 56588/1991 (3-56588), which comprises a process of calculating unit oven workings per one operational block based on a relationship between the number of operations per one day and the carbonization chambers installed. The operating process will be referred to as "second process" hereinafter. A further process comprises a so-called block operating process which is adapted to distribute installed carbonization chambers to each of operational blocks in a manner not to produce any surplus, as shown in FIG. 4. The process will be referred to as "third process" hereinafter.
Also, when the number of operators is sufficient to permit the operators to alternate in taking a rest, a continuous operating process is carried out wherein unit oven workings for a total amount of installed carbonization chambers are equally allotted on the basis of a target period of time between charging and discharging, to thereby eliminate an operation interrupting time. The process will be referred to as "fourth process" hereinafter.
Unfortunately, the conventional processes described above have the following disadvantages.
First, a cycle of discharge from an oven (hereinafter referred to as "oven discharge cycle") is kept constant throughout the carbonization chambers, resulting in a variation in carbonization time among the carbonization chambers, so that much labor is required to adjust heating conditions. Also, the oven discharge cycle for the same carbonization chamber is varied, therefore, adjustment of the heating conditions is restricted, leading to delay of carbonization and excessive carbonization which cause an increase in quantity of heat required for carbonization. Such disadvantage is peculiar to the first and second processes described above.
Also, in the first and second processes, the delay in carbonization and excessive carbonization cause a quality of coke produced to be deteriorated and varied.
In order to concentratedly repair the whole coke oven, it is required to change the oven charge-discharge schedule to ensure a repairing time of the order of 1 to 6 hours. Unfortunately, this causes the oven discharge cycle after restarting of the operation to be substantially varied, resulting in the quantity of heat being increased and the quality of coke being deteriorated and varied. Also, interruption of operation required for repairing the coke oven leads to a decrease in production of coke. Such disadvantage is common to the first to fourth processes. FIG. 6 shows an example of an oven charge-discharge schedule for the third process which is so prepared that the operation is interrupted for three hours.